 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.properties;

 import org.eclipse.core.internal.indexing.IndexCursor;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.QualifiedName;

 /* package */interface IVisitor {
     /**
      * Answers whether the visitor requires that the <code>IStoredProperty</code>
      * has its value filled when matched from the store.
      * <p>
      * Retrieving the property value may be expensive in time and memory usage
      * (dependent upon the size of the property value.)</p>
      * <p>
      * If the visitor answers true, the <code>visit()</code> method will be
      * invoked with a complete property; if the visitor answers false the property
      * value will be <code>null</code>.
      *
      * @param resourceName the name of the matching resource
      * @param propertyName the name of the matching property
      * @return whether the visit method requires a value
      */
     public boolean requiresValue(ResourceName resourceName, QualifiedName propertyName);

     /**
      * Performs whatever actions are appropriate to the visitor when a
      * match is made to the property store query.
      * <p>
      * This method is invoked each time a matching entry is found in the store.</p>
      * <p>
      * Note that the property will have a <code>null</code> value if the <code>
      * requiresValue()</code> method returned <code>false</code> for this property.
      *
      * @see IndexCursor
      * @param resourceName the matching resource.
      * @param property the matching property.
      * @param cursor the cursor positioned at this property in the <code>IndexStore</code>.
      */
     public void visit(ResourceName resourceName, StoredProperty property, IndexCursor cursor) throws CoreException;
 }

